Stormwater retention and detention systems (for example, also known as storage structures with controlled outflow devices) are systems typically installed underground, that are used for accommodating surface stormwater runoff by diverting and storing water to prevent pooling of water at the ground surface.
Although stormwater (or water) is being referenced generally for descriptive purposes, such liquid identification for this patent can be interchangeable with stormwater, groundwater, drinking water, irrigation water, sewerage and wastewater, or industrial process water and the associated characteristics of such specific liquid being referenced for management purposes.
Liquid retention and detention systems typically consist of a structural support component (in the form of a container or vessel), with an available storage volume and a controlled outlet flow device for metering discharge from the system. These systems are typically installed underground, but can be designed for above ground applications. The industry historically locates these systems at a lower elevation than the collection basin surface (or system) so as to take advantage of the natural potential energy (head) associated with liquid flows to eliminate the need for mechanical devices such as pumps. Stormwater systems are typically located in close vicinity of the collection area, such as under a parking lot, roadway or building to optimize the use of the land area.
Other uses of storage and controlled outflow systems involves having greywater piped into the system directly from a building, groundwater which flows into the system through the ground, and blackwater, which is pumped into the system. Greywater includes wastewater generated from domestic activities such as laundry, dishwashing, and bathing, which can be recycled on-site. Blackwater includes greywater and anything that goes down drains, including toilet water.
Water storage with controlled outflow systems are generally large structures, and thus, may be provided as modular systems that can be assembled in pieces yet meet the same intent as a singular large structure. There is a need to provide modular systems because modular systems are easier to install, allow for greater design flexibility, and have lower installation costs than nonmodular systems. This is because water storage and controlled outflow systems typically require very large storage volumes requiring heavy structural components to contain them.
It is also an advantage for the structure of a modular system to be accessible and large enough for a person to enter the system in the event servicing of a module is required.
For example, such systems are manufactured of concrete with a reinforced steel core, or interconnecting pipes or chambers constructed of metal or plastics supported by a structural stone bedding and backfill material or ponds with an open water surface.
There are various existing designs of water storage and controlled outflow systems that are known in the art. These systems, while being designed to retain and detain water and/or displace water, however, have significant disadvantages that are overcome by the presently described invention.
U.S. Pat. No. 7,621,695 to Smith et al. discloses a subsurface cubic water system having modules with pillars forming a generally cruciform cross section. U.S. Pat. No. 7,344,335 to Burkhart discloses a water retention system having modules with continuous lateral and longitudinal channels, the continuous lateral and longitudinal channels extending from one end of the system to the other allowing for unimpeded flows in any or all directions during operations.
U.S. Pat. Nos. 7,056,058, 6,779,946 and 5,810,510 to Urriola et al. disclose a transport corridor drainage system having vertical channels and no horizontal deck. The '510 patent in particular discloses an underground drainage system having channels for flow.
U.S. Pat. No. 5,249,887 to Phillips discloses an apparatus for control of liquids having modules in series; U.S. Patent Application No. 2009/0226260 to Boulton et al. discloses a method and apparatus for capturing, storing and distributing water; and U.S. Patent Application No. 2009/0279953 to Allard et al. discloses modular units having an arched opening in each of six faces, such that passages for water flow extend through the center of the structure to each opposing face.
All of these designs, however, while being designed for the storage of water and function as large holding vessels for water, do not provide a system that is designed for providing indirect flow of water internally within a system. Furthermore, these systems do not disclose the use of a modular system having beams, walls and/or weirs, the modular system allowing for a serpentine or semi-serpentine flow of water within the modules and system.
Instead, existing systems have primarily functioned as large holding vessels for water, with treatment and flow control devices occurring outside of the system structure. Existing systems do not apply and integrate the principles of treatment or internal flow control methods that affect the velocity, the potential energy (head), time attenuation (retention) flow and/or turbulence control within the system. Flow controls, such as weirs, baffles, walls, orifices, standpipes and particular intended combinations of these devices, have not been provided internally in the existing systems. Furthermore, existing systems have not used these flow controls to cause water to purposely flow indirectly internally within the system for a means of secondary application such as treatment or conditioning.
Indirect flow of water internally within storage with controlled outflow systems has advantages over existing systems. Such a design allows for water to flow through a system for a controlled period of time. Indirect flow of water internally through a storage and controlled outflow system allows for the amount of time that water is present within the system to be optimized based upon the cross-sectional area of the system (i.e., the water stays in the system for the optimal amount of time based on the cross-sectional area of the system). This allows the water to be controlled within the system and also allows for water to accumulate in the system in a controlled and systematically intended manner. This allows for optimal increased storage of water in the system and the application of controlling the flow for other purposes such as treatment, temperature regulation, flow attenuation, and other purposes for water treatment and conditioning.
Indirect flow of water internally within a retention and detention system also allows the water to be controlled within the system to achieve treatment. This allows the water to be treated or conditioned as the water flows internally within the system. A system with a purposely intended controlled indirect flow, prepares the proper environment and conditions conducive to treatment and conditioning applications. Such an intended system design can create the optimum conditions for gravity separation (allowing for both oil water separation and particle separation), neutrally buoyant materials control, trash, debris and solids control, filtering, extended detention for nutrient reduction, temperature reduction, and chemical addition. The result of such a system design may be for the use of conditioning process water or for the removal of various components (either soluble or insoluble) from the flow regime prior to the water being discharged from the system. Furthermore, indirect flow of water internally within a system has other advantages as it allows for compartmentalized flow within the system that allows for various configurations and interchangeability of applications of the system to be provided.
Additionally, indirect flow of water internally within a system may allow for systems where one compartment of the system has a solid floor, while other compartment of the system has a permeable or gravel floor, allowing water to exit the system through the bottom. This may allow for one compartment of the system to be used for water retention, while having other compartments of the system used for water treatment or other applications. In short, a system with internal indirect flow of water is desirable as it solves problems related to uncontrolled flow, such as “short circuiting”, that is common in existing systems. Moreover, internal indirect flow of water solves problems that have not been recognized in the prior art, as it requires the use of beams or other such diversionary structures that diverts the water in an indirect manner. These additional beams and/or material for diverting the water in an indirect manner involves creating systems with additional cost as extra concrete and/or other material used to divert water has to be supplied as material costs.
A system incorporating beams is also more flexible then existing systems as the beams allow for control of the water directing it into a “low flow channel” formed by the restrictive nature or the beam as a barrier and a function of the cross sectional area of the water surface area below the level of the beam. As a result of this concept, for a given period of time greater amounts of water may remain in the system with the beam design, allowing for an increased detention capacity of the system for its available storage volume. The increase in detention time is a direct result of the extended attenuation time (or flow lagging) caused by the indirect serpentine flow pattern allowing for the water to remain in the system for a longer period of time.
As none of these existing systems provide for a design having indirect flow, it is desirable to provide a design that achieves these objectives, and achieves the advantages of such a system. It is further desirable to provide a modular system that hinders the flow of water in a lateral direction, while allowing for longitudinal flow. It is further desirable to provide a modular system that hinders the flow of water in a longitudinal direction, while allowing for lateral flow.
It is also desirable to provide a system that allows for serpentine or semi-serpentine flow of water in the system and allows for control of the flow of water. It is further desirable to provide for a system that allows for internal treatment and conditioning applications of water and also allows for storage and controlled discharge of water. It is also desirable to provide a system that allows for optimal treatment of the water.
Such a water storage with controlled outflow system is novel and unobvious over the prior art. Existing systems have not recognized the problems associated with controlling “short circuiting” by establishing the indirect flow of water through a system where the level of the water is controlled by the height of the beams, walls or weirs. Such existing systems, and persons of skill in the art making such systems, would not have recognized the problem of having indirect flow as all of the existing systems simply are designed principally to store water and work to move the water through the system directly or work to retain water. Existing systems are not designed to control the flow of water in an indirect manner and to maximize treatment of the water.
Having systems with beams may allow for internal indirect flow when the level of the water is below the level (or top of the vertical height) of the beams in the system. In occasions where the level of water is higher than the top of the vertical height of the beams, such as a 2, 10, 25, 50 or even 100 year storm, it is advantageous to have beams as the system may then allow for flow of water that is unimpeded in all directions. This is advantageous over having impervious walls instead of beams, as water would not be able to pass thru the walls. However, a system incorporating impervious walls is also contemplated by the disclosure and utilized specifically when an impeded barrier is required for an application purpose.
A system that has internal indirect flow achieves both storage and controlled outflow capabilities, while allowing for treatment of water, and allowing for water to move through the system in an indirect manner, which optimizes by attenuation (or flow lagging) the amount of time the water is retained in the system. A system that achieves these objects, such as described below, is certainly desirable. Furthermore, a system that controls the velocity, the potential energy (head), time attenuation (flow lagging), flow and turbulence internally within a system is also desirable. A system that has a positive impact on the environment is also desirable.